Reflex Lab

In this lab we tested different multiple different reflexes, such as the photopupillary reflex and Patellar reflex. From the notes we learned that reflexes are "rapid, predictable, and involuntary responses to stimuli." Which means that the information does not reach the brain, the nerve impulses go to the spinal cord.

We first tested the photopupillary reflex which when stimulated causes the iris to contract and pupil to reduce in size. When a bright light was shined in my eye this reflex was triggered, the result was my pupil decreases. This occurs to protect the eye by lessening the amount of light entering it. You can see this occurring in the video below, right when my hand is removed from my eye.

Second we tested the Knee Jerk Reflex or the Patellar reflex. This reflex occurs when the part below the knee is tapped causing the the thigh muscle to stretch. There is only one synapse to allow this reaction to occur. When my classmate tapped my knee with the rubber instrument my knee swung into a flexed position. Humans have evolved this trait to be able to modify their body to maintain balance.

Third was the blink reflex. Basically demonstrates how when something comes close to our eyes we close them to protect our eyes from damage. When I threw a cotton ball near my classmate's face she blinked, demonstrating this effect.

Fourth was testing plantar flexion yet again, but also testing for Babinski's sign. In this test my classmate took a pen and ran it along the bottom of my bare foot. The normal response to this was toes flex and come close together, but my response was Babinski's sign (which means it did the opposite, toes spread apart and upward). I displayed this sign because I am a dancer and have a lot of nerve damage in my feet. People who have multiple sclerosis also display Bainski's sign because of their nerve damage.

In the fifth and final testing we did a reaction time test. This was not a reflex test because it incorporated visual and motor translation. We dropped a ruler above someone's hand and measured how long it took for them to catch the ruler. We did this normally with no distractions and then a second time while texting. The class average for non texting (females) was .1942 seconds, but the reaction time for the same people while texting was .2572 seconds. Even though it doesn't seem like a huge difference to be a hundredth of a second more or less, but when driving that could be the difference between stopping safely behind a car or ramming into it. Driving while texting is very unsafe because it decreases your ability to react as quickly. Our brains cannot multitask they can only jump between activities.